They look like something designed for space travel, but the napping pods made by MetroNaps are being used by a handful of law firms and almost all of them are small, according to the company’s CEO.

The large firm is White & Case, which installed two of the pods last year at its Washington, D.C., office, the Am Law Daily (sub. req.) reports.

White & Case partner Francis Vasquez Jr. tells the Am Law Daily the pods have been well-received, though many workers are reluctant to admit they use them. Vasquez, however, says he has woken up refreshed after using them.

The “energy pods” are lounge chairs with a domed privacy visor and they can play “relaxation rhythms” while the user snoozes. After 20 minutes, the pods use vibrations and soft lights to wake the user. The cost is $13,000 per pod.

MetroNaps CEO Christopher Lindholst tells the Am Law Daily that the pods have not caught on in conservative industries and institutions.

Law firms have “not been a significant vertical” market, Lindholst said.